General purpose relay



Aug. 17, 1954 E. L. EARLE 2,686,850 GENERAL PURPOSE RELAY Filed Oct. 26,1950 INVENTOR EDWIN L.. EARLE ATTORNEY Patented Aug. 17, 1954 2,686,850

UNITED STATES PATENT OFFICE 2,686,850 GENERAL PURPOSE RELAY Edwin L.Earle, Chicago, 111., assignor, by mesne assignments, to InternationalTelephone and Telegraph Corporation, a corporation of Mary landApplication October 26, 1950, Serial No. 192,260

2 Claims. 1

This invention relates to electro-magnetic relays and more particularly,general-purpose electromagnetic relays of the type used in the telephonecommunication industry.

This invention is a direct improvement on the relay apparatus disclosedin the application of Arthur et a1. Serial No. 20,196, filed April 10,1948.

A general object of this invention is to provide reliable andeconomically produced relays suitable for meeting a large number ofvarying switching requirements.

A specific object is to provide a new and improved structure whichfacilitates alignment of the armature keeper.

A further specific object is to provide a relay structure of theforegoing character in which the number of actuating ladders required tomeet the large variety of switching needs is minimized.

In the relay construction to which this invention is directed, insulatedladder-type switch actuating members are associated with spring setsstacked in a sequence according to the number of spring memberscontained in the stack, whereby the diiferent ladder forms may belimited to a minimum number. After the limited minimum number of laddershapes is determined, this invention effects a further reduction inladder forms by providing a double row of steps oppositely disposed onthe edges of the same ladder, each row accommodating a specificallydifferent combination of spring-set sequences. This arrangement makes itpossible to cut in half the number of standard ladder configurationsrequired for the noted system of stacking.

To assure proper aligned association of the armature of the relay withthe spring stack, a raised portion is provided on the upper surface ofthe magnetic support plate for cooperation with a slot provided in thearmature keeper, and with the mounting screw which extends through thekeeper slot, so as to properly align the keeper, which in turn, properlyaligns the armature with the switch stack. A resulting feature is thatthe armature alignment with the switch assembly is predetermined andautomatically accomplished incidentally to assembly of the relay.

Other objects and features will appear as the description progresses.

Fig. 1 is a top plan view of a relay embodying the invention shown witha portion of one upper back contact spring of the switch assembly brokenaway to reveal the shape of the uppermost front contact spring asrepresentative of the shape of the remaining front contact springs.

Fig. 2 is a side elevational view of the relay of Fig. 1.

Fig. 3 is a top plan View of the relay with its switch assembly removed.

Fig. 4 is a front elevational View of the relay shown in Fig. 3 with itsarmature assembly removed.

General structur e Referring particularly to Figs. 1 and 2, the relayincludes an electromagnet I0, its armature II, a twin stack switchassembly I2 both stacks of which are actuable by the electromagnetthrough the armature, and an L-shaped return plate I3 on which theswitch assembly and armature are mounted.

The electromagnet I0 includes a coil I4 and a cylindrical magnetic coreI6 extending therethrough. The rear end of the core is threadedlyreceived within an opening in the vertical portion of the return plate I3, rendering it longitudinally adjustable. A locknut I1 is provided toretain the core in a desired longitudinal position of adjustment.

The electromagnet I0 has a rounded front spoolhead I8 fiat on its upperedge, and a square rear spoolhead I9 which may be seen in profile inFig. 4. The fiat edges of the spoolheads retain this coil againstrotation by reason of the squared relation of one edge of each with theunder surface of the horizontal portion of the return plate I3.

Rcarwardly extending winding terminals 20 for coil I4 are located in arow along the lower edge of the rear spoolhead I9. The upstanding baseportions of the terminals are kept out of engagement with the verticalrear portion of the return plate I3 by an insulating spacing collar 2|,which encircles the core I6 between the return plate I3 and thespoolhead I9.

The coil is retained in its longitudinal position at the front of theelectromagnet by a spring clip 22 engaged within an annular groove inthe front portion of the core.

As shown in Figs. 1, 2 and 3, the armature is held in position at thefront of return plate I3 by a keeper-member 23. The keeper-member 23 isprovided with a pair of arms 24 preferably disposed, as shown in Fig. 2,so that they make about equal angles with parts 26 and 27 which comprisethe angularly disposed arms of the bellcrank armature I I. The smoothworking surfaces of such arms bear against the bent portion of armatureI I to prevent its upward or forward displacement.

To enable th keeper-member 23 and armature to be mounted on the returnplate, an aperture or cut-out portion is provided in the arm 2% ofarmature H through which a flat bifurcated extending portion 28 of thekeeper may be fastened to the return plate H3. The bifurcated extensionportion comprises a pair of arms 2S3 defining a slot within which afastening screw 38 is snugly accommodated for threaded ngagement with ahole in the top of the return plate is so that the arms 29 can be eithertightened against the. return plate or slidably disengaged from thereturn plate upon loosening the screw 3%.

A raised cylindrical projection 31 is formed on the upper surface of thereturn plate just behind the screw as and underlying the front part ofthe switch assembly by a semi-perforating operation on the under side ofthe return plate. The raised portion 3! cooperates with the slot in thearmature keeper to key it against rotation while the retaining screw 30is being tightened in place. Besides keying the keeper against rotationthe raised portion 3! is also used as a guide to locate the keeper inproper position for association with the armature ii. That is, while thekeeper 23 is being mounted, the screw so and the raised perforation Blboth act to automatically align the keeper laterally by reason of theirfixed location one behind the other on the return plate l3. and theirsnug fit within the slot formed in the keeper extension 28 by the arms29. The length of the slot may be made such that the keeper can belongitudinally positioned by merely sliding it rearwardly until the endof the slot hits the screw 30. With such an arrangement, mounting andremoval of the keeper and armature may be effected without completeremoval of the screw 30, and both parts may be mounted on the returnplate without the need for special lateral or longitudinal aligningprocedures.

In its deenergized state, stop position of the armature is regulated bythe setting of the screw 33 in the keeper-member 23, while a locknut 34associated therewith locks the screw 33 in a desired position. AU-shaped residual plate 35, shown in Fig. 2, is applied to the armatureand then crimped in place to ap pear as shown. Such plate, whenemployed, lies between the core and the armature. By striking the core,it holds the. armature out of contact therewith to insure that a desiredamount of operating air gap remains unclosed with the armature in fullyoperated position. This is commonly referred to as the-residual gapwhich has a length determined by the thickness of plate 35, and controlsthe release characteristic of the relay, as is commonly known.

Switch assembly The twin stack switch assembly of Figs. 1, 2, andincludes a cap-plate 3?, base plate 38, and parts clamped between themby screws M) which pass through openings in the cap-plate andinterveningparts to the base plate, wherein they are threadedly received. Twoopposed columns 42 and 43 of the contact sets are included in the sameunitary assembly l2. This construction enhances rigidity and reduces thenumber of assembly and clamping screws required. The switch assembly isreadily installed in position on return plate l3 and is simply securedby two mounting screws fill which pass through the assembly for threadedengagement with apertures Ala in the upper surface of the return plate.The switch assembly lies fiatly upon the return plate with theprotruding ends of clamping screws the normal or back 40 thereof beingreceived in provided clearance openings 49a in the return plate.

Referring now to Fig. 5 wherein the left hand column 43 is shown inprofile to include four commonly denoted types of contact sets, themake-before-break set (fixed blade 44 and traveling blades 25 and 56)the break-make set (fixed blades 48 and 5t and traveling blade 49), thebreak set (fixed blade 5! and traveling blade 52), and the make set(fixed blade 55 and traveling blade 54) A spacing member 53 having thesame thickness as the traveling blades, is used in the tongue portion ofthe assembly between the traveling blades 52 and 54, to balance theassembly by compensating for the travel or motion of the adjacenttraveling blades. The right hand column may or may not include similarsets.

The traveling blades of both columns are moved by a pair of similaractuating ladders .53 which move the blades into and out of electricalcontact with the fixed blades of their respective contact setsinresponse to movement of the associated armature. The ladder 58 which isprovided for column 42 is actuated simultaneously with the ladder 58 ofcolumn 43 by the armature. Each of the contact blades of columns $2 and43 has a terminal portion 6!] for the attachment of cir cuit wires. Theterminals are staggered as shown in Fig. 1 for wiring convenience.

The traveling blades d6, 39, and 52 of the normally closed contacts incolumn 43 are downwardly tensioned by a preforming operation, and innormal position exert sufiicient contact pressure against theirrespective fixed contact blades 44, 48, and El to insure that reliableelectrical connection is established therebetween. The traveling blades15, and 54 of the normally open contacts of each column are slightlytensioned downwardly to insure that they will return to their normalopen position after operation.

The fixed blades are sufficiently rigid to withstand pressure exertedagainst them by their respective traveling blades and are all of similarconstruction with th exception of fixed blade M, which is upwardlyoffset at the front. Blade 44 is constructed in this manner to permitits associated make-before-break contact set to perform its usualfunctions with the actuating blade 5 thereof in an intermediate positionbetween blades 44 and it, which places the control thereof at the samepoint or level as that of the breakmake sets. It is important to havecontrol of the different sets thus fixed at the same level since theycan then be actuated by the same step on the actuating ladder 53, makingit possible for the two sets to be interchangeable and thereby promotingadaptability to operation of a number of switches comprising differentcontact set combinations with a minimum number of actuating ladders.

Each actuating ladder 5B is operatively associated with its respectiveswitch stackup by being passed through a series of aligned slotscomprising one slot in each traveling blade and then placing its stepsin en agement with the respective blades which it is to acuate. Theladder slots are somewhat longer than the width of the ladder which theyaccommodate so that the ladder may be readily passed through them.

To secure each of the ladders 58 in a vertical position in engagementwith their traveling blades, a pair of retaining springs 2'6 and H areprovided at the bottom and top of each stack respectively. A narrowelongated aperture is provided in each retaining spring to permit thespring to snugly accommodate an end of the ladder of its stackup. Theupper retaining spring the return plate l3.

Numerous combinations of contact sets are possible in switch assembliesof this type; and for this reason a large number of actuating ladderforms are usually required to accommodate all the possible combinations.As pointed out above, the number of actuating ladder forms may bereduced somewhat by arranging some of the contact sets so that fewerstep shapes and spacing arrangements are required. To further reduce thenumber of ladder forms to meet all switch combinations, steps areprovided along both longitudinal edges of the ladder, thus making itpossible to adapt the ladder to substantially double the number ofarrangements of contact sets. This may be readily seen by viewing Fig. 6in which the actuating ladder 58, which was used spect to its positionin Fig. 5 so that the steps along the edge opposite that used in thestackup of Fig. 5 can be used with the second switch assembly. For moreready comparison, the ladder 58 is also shown in Figs. 7 and 8 in thepositions in which it is used in the assemblies of Figs. 5 and 6.

The assembly of Fig. 6 includes five contact sets, the break-make set(fixed blades 5! and 63 and traveling blade 62) the two break sets(fixed blades 65 and 68 respectively, and traveling blades 66 and 69respectively), spacer member 6'! and two make sets (fixed blades 72 andI4 and traveling blades TI and T2). The steps along the second edge ofladder 58 are spaced so that they will fit in engagement with thetraveling blades of this switch assembly. The ladder is thereby madecapable of fitting two entirely different switch assembly arrangementswhich have no relation whatsoever as far as their sequence of stackingcontact sets is concerned. Thus, it is readily apparent that the numberof standard froms of actuating ladders which might normally be requiredwith single sided ladders can be effectively cut in half by providingladders having steps along two edges thereof. practice, where twenty-oneladder forms might satisfactorily meet all combinations of contact setsnormally encountered, the use of double sided ladders will permit thisnumber to be cut to eleven ladder forms.

To enable an end for end reversal of the double sided ladder 58 so thatboth rows of steps can be associated with contacts in differentassemblies, a pair of projections are provided at each end of theladder; one of which is primarily a foot portion and a means forsecuring the ladder when it is disposed at the bottom of the ladder; and

the other, a somewhat shorter and narrower portion which engages thearmature for actuation of the switch assembly when disposed at thebottom of the ladder, and as a means for retaining the ladder whenlocated at the top. As shown in Fig. 5, the foot projection 78 at thebottom of the ladder is engaged within an aperture in the lower ladderretaining spring 16, and in passing through the aperture it comes intocontact with the upper surface of the return plate I 3 upon which itrests. The aperture in the retaining spring 16 is of just the right sizeto permit the width of the foot projection 18 to fit therein Forexample, in

' posed at the bottom of the ladder.

snugly without play, thereby holding the bottom part of the ladder inposition. The shorter projection 79, as shown in Fig. 5, is disposedimmediately in front of the foot projection 18, and by reason of itsshorter dimension, the arm 26 of the armature l I can be slippedthereunder for operative association with the ladder. The projection 19is made sufficiently short so that a large enough clearance exists forthe end of arm 26 of the armature to be inserted under the projectionwithout disturbing or upsetting the ladder or switch assembly after theassembly is mounted on the return plate I3. Once the arm 26 ispositioned in underlying relation to the forward engaging projection 19,the normal back position of the armature is obtained by turning thebackstop screw 33 inward until contact is made by the arm 26 with theprojection 19 without lifting the ladder.

Fig. 5 also shows that the second foot projection and the shorterprojection 81 at the top of the ladder are disposed in reverse order tothat in which the corresponding projections are dis- That is, theshorter projection 81 at the bottom of the ladder is disposed behind thefoot projection. The ladder retaining Spring 11 this is convenientlypositioned to engage the armature engaging projection Hi to hold theupper part of the ladder in place. The aperture in the retaining spring11 thus need not be as large as that in the retaining spring I6 sincethe projections accommodated therein are of narrower width. By reason ofthe difference in size of the apertures in the retaining springs, theladder 58 can be oriented with the switch assemblies in only two waysrather than four which would be possible if both projections at each endof the ladder could be inserted in the apertures of either of theretaining springs l6 and 11. That is, when the foot projection 18 islocated at the bottom of the ladder, the ladder can be mounted in theretaining spring only in the manner shown in Fig. 5, and cannot beturned so that its front edge faces the rear, because the footprojection 89 at the top of the ladder will not fit within the aperturein the top retaining spring Tl. Correspondingly, when the footprojection 8D is located at the bottom of the ladder, as in Fig. 6, onlyone edge can be made to engage the traveling springs of the switchassembly while being held by the retaining springs, because the footprojection 18 at the top of the ladder cannot be inserted in theaperture of the retaining spring Tl.

As indicated, the retaining spring 11 is tensioned downwardly to assistin biasing the ladder 58 downwardly against the return plate [3. In thisrespect, it is to be noted that the cut-out portion between theprojections 89 and 8!, engaged by the retaining spring TE, as shown inFig. 5, is somewhat deeper than the cut-out portion between projections18 and T9 at the bottom of the ladder. The diiference in depth of thesetwo cut-out portions exists by reason of the fact that the two switchassemblies for which the ladder is designed each have a differentover-al1 height and the difference exists in order to make the retainingspring 77 provide the same biasing force for the switch assemblies ofboth Figs. 5 and 6. The depth of the cut-out portion between projections80 and iii, within which the biasing spring ll engages for the assemblyof Fig. 5, must therefore be greater than the depth of the cutoutportion between projections 18 and 19 engaged by the spring 17 for theassembly of Fig. 6 which has a greater over-all height.

As shown in Figs. 7 and 8, the steps provided along the edges of theladder 58 are formed by cut-out portions or notches N! through N9 in theedges which leave the steps as projections for engagement with thetraveling springs. The notches are of such width that sufficient spaceis provided above the engaging edges of the steps that association ofthe ladder in proper position for engagement with the traveling springsof the respective assemblies is easily accomplished. The distancebetween adjacent notches and the distance between each notch and thefoot located directly below is dependent upon the type of contact setswith which the traveling springs are associated. In this respect, itwill be noted that the distance between each foot of ladder 58 and thefirst moving contact blade with which the foot is actively associated inthe difierent switch assemblies (the distance from tip of foot 78 tonotch Ni and the distance from the tip of foot 89 to notch N9) is thesame. Similarly the distance from the foot and the second moving contactblade (the distance from the tip of foot 78 to N2 and the distance fromthe tip of foot 89 to N8) in each assembly is the same. From the secondstep on up, however, it will be noted that difierent distances existbetween the moving blades and the ladder foot, since the third contactset in Fig. is disposed above a set having three springs (the third orupper spring being a stationary spring), while in Fig. 6 the thirdcontact set is disposed above a set comprising only two springs. Thedistance between the second and third notches in the assembly of Fig. 6(N8 and N1 in Figs. 7 and 8) therefore is not required to be as large asthe distance between corresponding notches (N2 and N3 in Figs. 7 and 8)in the ladder for the switch assembly of Fig. 5. Subsequent adjacentnotches (N3 and and N1, N6, and N5 in Figs. 7 and 8) in each of theassemblies are more closely spaced because they are associated withcontact sets comprising only two springs. The assembly of Fig. 5 must ofnecessity be limited to a smaller number of sets within a given heightbecause the contact sets at its lower level include a greater number ofsprings and consequently occupy a greater portion of the over-allheight.

In the light of the above description, it is apparent that the ladderincorporated in the switch assembly, in being adapted to actuation ofmore than one stack or combination of contact sets, greatly reduces thenumber of standard actuating ladder forms required to meet thecombinations that might be encountered in practice. In addition, it isreadily seen that adjustment of the switch assemblies may beaccomplished before they are mounted on the return plate of the relay.Still further, adjustment of the contact sets may be effected even afterthe assembly is mounted on the return plate 13, independently of theassociation of the assembly with the armature. In other words, after theswitch assembly is mounted on the return plate and the ladder is biaseddownwardly on the upper surface thereof, each of the contact springs inthe assembly may be adjusted for tension by bending them for the desiredbiasing effect even before the armature is put in place on the magneticstructure of the relay. After such adjustment is accomplished, thearmature may be slipped in place and mounted on the relay withoutdisturbing the switch in any manner whatsoever. As pointed out above,the armature is then adjusted so that its backstop position is such thatits arm 28 just contacts either projection 79 or 8! respectively,without lifting the ladder.

Upon'energization of the electromagnet I0, the associated armature Hturns about its axis to bring its lower attracted'portion 27 intocontact with the dome end of the core 16 which provides an adjustablefront stop for the armature.

Upon deenergization of the electromagnet, the downward tension, of theassociated traveling blades of the switch assembly serve to turn thearmature to its normal position, and as indicated, the normal or backstop position of the armature is regulated by the setting of screw 33.Turning the screw in the opposite direction permits a more expandedreturn movement of the armature. Locknut 27, when tightened, locks screw26 in the desired position which in many instances will be dependentupon the residual gap which will provide the operatingtiming desired.

I claim:

1. An actuating ladder for electrical switching assemblies includingcontact sets spaced apart in a stackup, said ladder comprising astriplike member having its edges serrate to provide two rows ofactuating steps disposed respectively on opposite sides of the member,one row having the steps thereof spaced from each other difierently fromthose of the other row, thereby adapting it for operative associationwith a stackup of contact sets spaced apart different- 13 from thosewith which the other row may be operatively associated, said strip-likemember having opposite ends of which a portion has a lesser length thanthe overall length of the member, either longer end portion defining astop and either lesser end portion defining a means tobe engaged by anoperating member.

2. In an electrical switching device comprising a switch assembly ofstacked contact sets, means including a plate-like base for supportingsaid assembly, a switch actuating ladder comprising a strip-like memberhaving serrations providing separate actuating steps for said contactsets respectively, means for holding said ladder with its steps inoperative association with said contact sets, means included in saidswitch assembly biasing said contact sets downwardly to a non-operatedposition, means including an operating member movably supported on saidbase for applying force for upward movement of said ladder against saidbiasing means to a position of operation, said strip-like member havinga longer and a shorter lower end portion defining respectively a stop onsaid base and an abutment to be engaged by said operating member.

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